1. Field of the Invention
The present invention relates to apparatus and methods for trimming and forming wire leads of transistors and similar electronic components as preparation for installing the components on printed circuit boards. Pre-forming component leads is recognized as a useful technique in helping to assure proper positioning of components and to eliminate lead trimming after installation. The present invention relates specifically to apparatus for automatically transporting, aligning, and positioning electronic components and trimming and forming associated leads.
2. Description of Prior Art
The need for equipment to trim and pre-form the leads of electronic components such as transistors was realized early in the development of solid state electronics. Numerous machines have been constructed to perform the necessary functions semi-automatically; that is, to trim and form wire leads of components inserted manually into an aperture. Generally, apparatus of this type use dies to apply force to the wire leads and shape them in the required manner. Die movement is often controlled by an operator-actuated switch. Although the semi-automatic lead forming machines serve to make necessary modifications to components leads for easy installation of components on printed circuit boards, such devices are limited as to production rate because each component must be manually fed into position and subsequently removed after the forming operation.
Means for synchronization and linking of a lead forming apparatus to a feeding mechanism for the purpose of eliminating the rate restrictions imposed by manual feeding are disclosed in U.S. Pat. No. 3,548,998, and further disclosed in modified form with regard to the mechanism in U.S. Pat. No. 3,640,113. The apparatus described includes a transporting wheel to carry components to a plurality of stations where reciprocating dies trim and form leads with limited functions being accomplished at each station. Another example of a multistation processing device is to be found in U.S. Pat. No. 3,396,758.
Devices employing circular routing of components to various processing stations serve the intended purpose well, but as with most mechanical handling apparatus, extending of the route of travel generally decreases speed of operation and increases malfunctions due to mishandling. Also, moving a single die towards a fixed stop involves greater accelerations for a given rate and may complicate the forming step. The present invention improves the method of transistor and electronic component lead forming by simplifying the route travelled by the component being processed and providing for a pair of movable dies which converge upon the leads.